摘要:

Photoinjection efficiencies of holes from the carrier generation layer (CGL) into the carrier transport layer (CTL) in double‐layered organic photoconductors were measured by using a photoacoustic technique. The photoinjection efficiency depends on the concentration of transporting molecules doped in the polymer of the CTL. At low molecular concentrations, the injection efficiency is mainly limited by the low ability to transport carriers in the CTL. The concentration dependence of the photoinjection efficiency is found to be similar to that of hopping transport processes in the CTL. At high molecular concentrations, the photoinjection efficiency is limited by the free‐carrier generation process in the CGL.

ISSN:0021-8979    

DOI:10.1063/1.340505

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Al2O3films about 1000 A˚ thick were deposited on polished Si(100) substrates by the reactive ionized cluster beam method. It was found that the index of refraction, the etch rate in HF, and the microstructure of the films could be controlled by varying substrate temperatures up to 600 °C and acceleration voltages between 0.25 and 3 kV.

ISSN:0021-8979    

DOI:10.1063/1.340506

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The emission of visible radiation from reverse biased amorphous silicon carbidep‐i‐njunctions at room temperature was observed. The heterostructures were made by successively depositing boron‐doped amorphous silicon carbide‐intrinsic amorphous silicon carbide‐phosphorous doped amorphous silicon on to indium‐tin‐oxide coated glass. The optical gap of thep,i, andnlayers were 2.0, 2.25, and 1.7 eV, respectively. The reverse current producing the radiative emission is mainly due to a field‐enhanced thermal injection mechanism. At low‐current densities the total light emitted is proportional to the fifth power of the injected current. At higher injections, however, it becomes quadratic. These power law dependencies are interpreted in terms of electron recombination with trapped holes and band‐to‐band bimolecular recombination, respectively.

ISSN:0021-8979    

DOI:10.1063/1.340507

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Rh4Si5formation occurs by two different mechanisms, depending on the film geometry. Thermal annealing of a Rh film on a silicon substrate results in the formation of Rh4Si5at about 850 °C by a process described as ‘‘nucleation controlled.’’ Alternatively, when the film consists of thin Rh/Si multilayers, Rh4Si5can form at room temperature in a very rapid, self‐sustaining fashion that is the chemical‐reaction analog of the explosive crystallization process. This mechanism of explosive silicide formation, reported recently for the first time [J. A. Floro, J. Vac. Sci. Technol. A4, 631 (1986)], apparently occurs in the multilayer geometry due to the large driving forces and reduced diffusion lengths associated with this configuration.

ISSN:0021-8979    

DOI:10.1063/1.340452

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A novel idea is proposed to control the spatial mode profile of broad‐area semiconductor lasers in which the cumulative optical gain in the direction of light propagation is tailored by varying the effective length of the contact electrode across the lateral direction. Special interest is on a structure with the highest gain near the center of the device so as to favor the lower‐order lateral modes of oscillation. Preliminary experiments indicate that the concept works as intended.

ISSN:0021-8979    

DOI:10.1063/1.340453

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Planar InP/In0.53Ga0.47As photodiodes with boro‐phospho‐silicate glass (BPSG) layers as a Zn‐diffusion mask and as an InP surfacep‐njunction passivant exhibit stable, reverse‐bias leakage‐current characteristics at 220 °C for more than 104h. Based on these results, estimates of the time required for the leakage current at 70 °C to saturate at 10 nA is, in the worst case considered, about 33 years. As a passivant and diffusion mask, BPSG compares favorably with silicon nitride.

ISSN:0021-8979    

DOI:10.1063/1.340454

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We propose the use of a simple electric network model to estimate electron temperature for Cd iand Cd iiby estimating the gain and population inversion for a recombination laser. The temperature estimated for a Cd iilaser is in agreement with that of an experimentally observed value.

ISSN:0021-8979    

DOI:10.1063/1.340455

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We present results showing charge‐state separation of an ion beam in a purely cylindrical geometry, using the azimuthal magnetic field of a straight conductor. This geometry, which we refer to as a current coaxial lens, has advantages for the analysis of intense ion beams where it is important to minimize space‐charge blowup of the beam due to loss of space‐charge neutralization.

ISSN:0021-8979    

DOI:10.1063/1.340456

出版商:AIP    

年代:1988

数据来源: AIP